Hereditary angioedema (HAE) is a rare autosomal dominant disorder most often caused by variants of the SERPING1 gene encoding C1-inhibitor (C1-INH) with impaired production (type I HAE-C1-INH) or dysfunctional (type II HAE-C1-INH) forms of this serpin, a polyvalent inhibitor of proteases of the contact system, fibrinolysis and complement. Here, SERPING1 is linked to hereditary angioedema.